基本SQL排序依据查询

Question

下面的查询工作正常，并返回正确的结果，因为我需要

select top 1 SID from vSTable where (ID in 
(select ID from Engine where Name='nnn' OR Name='mmm') 
and QuestionTypeID=1 and IsOfficial=1) order by vSTable.ITime desc; 

但是当我使用它像这样

declare @SVal as int 

set @SVal = select top 1 SID 
      from vSTable 
      where (
       ID in 
        (select ID from Engine where Name='nnn' OR Name='mmm') 
       and QuestionTypeID=1 
       and IsOfficial=1 
      ) order by vSTable.ITime desc; 

我靠近选择语句

错误不正确的语法

Answer 1

将括号中的select语句包装起来

declare @SVal as int 

set @SVal = (select top 1 SID 
      from vSTable 
      where (
       ID in 
        (select ID from Engine where Name='nnn' OR Name='mmm') 
       and QuestionTypeID=1 
       and IsOfficial=1 
      ) order by vSTable.ITime desc); 

Answer 2

您的语法有点不合适。这应该工作：

select @SVal = (select top 1 SID from vSTable where (ID in 
    (select ID from Engine where Name='nnn' OR Name='mmm') 
    and QuestionTypeID=1 and IsOfficial=1) order by vSTable.ITime desc) 

请注意，您可以使用SET或SELECT进行该分配。